2003-07-13 15:59:12

by Peter Osterlund

Subject: Incorrect timeout in CDROM_SEND_PACKET ioctl in 2.5 kernels

The CDROM_SEND_PACKET ioctl passes a struct cdrom_generic_command from
user space, which contains a timeout field. The timeout is measured in
jiffies, but the conversion from user to kernel jiffies is missing,
which makes the timeout 10 times shorter than it should be in 2.5
kernels on x86. This causes CDRW formatting with cdrwtool to fail. The
following patch fixes this problem.

--- linux/drivers/cdrom/cdrom.c.old Sun Jul 13 16:34:37 2003
+++ linux/drivers/cdrom/cdrom.c Sun Jul 13 15:19:11 2003
@@ -295,6 +295,8 @@
#define cdinfo(type, fmt, args...)
#endif

+#define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
+
/* These are used to simplify getting data in from and back to user land */
#define IOCTL_IN(arg, type, in) \
if (copy_from_user(&(in), (type *) (arg), sizeof (in))) \
@@ -2171,6 +2173,7 @@
return -ENOSYS;
cdinfo(CD_DO_IOCTL, "entering CDROM_SEND_PACKET\n");
IOCTL_IN(arg, struct cdrom_generic_command, cgc);
+ cgc.timeout = MULDIV(cgc.timeout, HZ, USER_HZ);
return cdrom_do_cmd(cdi, &cgc);
}
case CDROM_NEXT_WRITABLE: {

--
Peter Osterlund - [email protected]
http://w1.894.telia.com/~u89404340

2003-07-15 13:46:59

by Jens Axboe

Subject: Re: Incorrect timeout in CDROM_SEND_PACKET ioctl in 2.5 kernels

On Sun, Jul 13 2003, Peter Osterlund wrote:
> The CDROM_SEND_PACKET ioctl passes a struct cdrom_generic_command from
> user space, which contains a timeout field. The timeout is measured in
> jiffies, but the conversion from user to kernel jiffies is missing,
> which makes the timeout 10 times shorter than it should be in 2.5
> kernels on x86. This causes CDRW formatting with cdrwtool to fail. The
> following patch fixes this problem.

Looks fine, applied.

--
Jens Axboe